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D. Piolle

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Everything posted by D. Piolle

  1. "Pietro" da Mantua ! indeed. Otherwise he would surely have made even more of his exquisite instruments.
  2. This is not exactly my feeling.
  3. I read a good number of manuscripts, including in old Italian dialects. You have to search in specific chapters about the preparation of the oils. In Mary Merrifield 's treatise, though I found transcription/translation mistakes, you can find a whole lot of good infos from older treatises. There's a text about how to wash the oil. ( a transcription by Charles Eastlake if I remember correctly). After all, You cannot find everything in books, and some are difficult to interprete though very interesting. Otherwise some of us would stop spending so much time in searching for the so-called holy grail and stick directly to the proper job. Having said that, I don't mean to offend you at all. Experiments are sometimes the best way to learn. I did a lot of craps and messed a lot with varnish, but it taught me a lot. Also, I attended to specific varnish making and varnish related courses. And served once as an assistant to François Perego for example. Those courses are a good starting point as well. And the first thing to think about is always safety and preparation, as cooking varnish could be very dangerous. Friendly. Dave.
  4. Perhaps this type of devices might have helped for long period cooking at relatively constant temperatures the vessel was surely placed in sand. But it would need several persons taking turns, paying attention during hours and even days and nights. Anyway there is no easy answer.
  5. This is also my understanding. At least the hydrophilic part of phospholipids. I agree on the cooking. In my experience, washing the oil also does a noticeable difference concerning stickiness of the varnish film. Many friends have also noticed a difference.
  6. Catholic institutions also had an important hand on forests products and timber sales. The apothecaries also learned a big part of the knowledge from monks, as, for example, the Dominicans. The church ruled the society.
  7. Not all , unfortunately... There are still people who think that cooking the oil is sufficient. Just because it's written " pure" or " for artistic purpose " on the container. There are also people that prefer to buy their varnish, which is actually fine. And actually it seemed to be the rule years ago.
  8. Of course it does ! As long as you mix things together, Anything matters.Including the proportion and properties of other resins. Cooked larch resin in conjunction with mastic or dammar or sandarac or copal, in a medium or a varnish will look very much like enamel and might be very bright. The case of sandarac is also tricky, as"Tetraclinis articulata"( cypress family tree ) is present in the southern Alps, and could be very easily confused in my opinion with the much more common "juniperus thurifera" ,also a cypress family tree, but a juniper, from the same area. They are very alike in the way they look ( with small differences though), but the resin of each particular tree surely behaves differently. As they are species from the same family and they look almost the same, people surely didn't consider any difference.
  9. I made pictures last week for people interested to see what it looks like.
  10. Thank you so much ! I think it is not even possible to find "bijon" suppliers. Even informations about it are really scarce. Too many people are simply not aware of its existence. This material is not something you can find on every larch. The average of trees that exude "bijon" is low. it is not worth for modern business and industry. The painter Xavier de Langlais was interested by this exudate,when, in his time (almost) no one had interest in it. it was no longer used since a long time. He said the best quality of larch resin is from far the one that naturally shed from the tree. By the way , you can simply call me Dave , or David. As you wish.
  11. The way the resin is cooked and also many other factors have an influence on thermo-sensitivity. . Slacked lime is supposed to increase the heat resistance of the resin, as some of you already know... in old codex(manuscripts) one can read very often about the cooking : " low and slow". In my humble opinion, if one doesn't wash the oil, it could also make the varnish to remain (a bit) sticky, especially in warm weather. Of course the quality of the oil, the way it has been extracted, are important factors as well. Too much of a drier could also damage the oil and actually be bad for the polymerisation. At first the varnish dries and then get sticky in a little while. All that is actually not always easy to control.And to be honest, I find it hard to get certainty and draw a solid conclusion.
  12. Thanks so much for your kind words and availability, as usual. :-) Congrats for the new videos, always a pleasure to watch them !!
  13. HI Davide. First : Thank you so much for generously sharing your experience and recipe! Actually I talked about using rock-alum instead of using ammonia. Rock-alum apparently helps the casein to dissolve. About the interaction between alum and calcium hydroxide, I am not sure but would be surprised if something bad happened. Perhaps someone with a much bigger chemistry background could answer. I need to search in my folders, but seem to remember a recipe calling for distilled water, casein, calcium carbonate (not sure) and rock-alum to dissolve and make the casein transparent. I 'll be back soon with the answer ( relying on this particular document). Have a good afternoon everyone.
  14. I read somewhere in this topic about the transparency of the casein based emulsion filler. One can add rock-alum to increase its transparency.
  15. Good evening Davide, Is it possible to know if you cook the mastic before doing the ground ? I know mastic and dammar spirit varnish can look very nice on top of the wood prepared with lime-casein filler. as long as you apply a very thin coat , otherwise the resin in the ground coat might want to soak the oily part of the oil varnish put on top of it. It happened to me. and it is not funny at all.
  16. Hello all , Back in the forum after 3 years of absence. Joe , you are right , and this is one of the reasons why I prefer to rely on my botanical knowledge and background. I collect my own resins and exudates as much as possible. There is so much to say about the subject , I don't know where to begin. 1- We must consider pure fluid larch resin, extracted from the tree by tapping or ( more likely ) doing a hole in the trunk. 2 - There is another type of exudate from the larch, we call it "Bijon" in the French Alps. " Bijon " is a thick reddish-brown resinous product that naturally exudes from the larch, often when the bark of old specimens have cracks. This is yet a different product. It actually is a thick material and if really dry, could be very tough, very hard and very difficult to collect. If you manage to collect some ( without breaking fingers), you will often have some bits of the tree bark coming with it. ( my experience ) 3- " Venetian turpentine " is an obscure name for such a product . Centuries ago it might well be the filtered or purified "Bijon" that was sold as "Venetian turpentine". 4- Both of those contain larixyl acetate which is a wonderful plasticizer and typical from the larch. That could give the dried film a really good resistance and resilience, unless it has been cooked too hot (over 220°c if remember well ) or too long, and then get destroyed. My opinion is Bijon is a much better product to start with for many reasons, and I am convinced the cooking time could be reduced in this case... Just a word about Alpine fir ( abies pectinata ) resin : it is really difficult to collect. And even when not cooked ( the real stuff I mean ) it dries much more quickly than any other exudate, and reduce very much in volume, with air exposure. Also different pines resins behave differently when cooked in a varnish. Some like "pinus pinaster" seem to be more acidic than others like "pinus halepensis". The term Greek pitch refers to the pitch extracted from the "pinus brutia" from Calabria which was at that time a part of Greece and not Italy. I attached two pictures of larch exudates samples I sent to a friend for the purpose of analyses. In the picture with the small pots one can see three pots with "bijon" at different stages of oxidisation, the one at the right is fresh pure fluid larch resin. The other picture shows a big pot with fresh larch resin. Sorry for the low-quality of the pictures. Perhaps some food for thoughts, I hope. Bye-bye everyone
  17. I had a very bad experience about it , cause the resins I used were soluble in the oil of the the top coats ( oil varnish ) , and when the brush touched the first coat of spirit ( of turpentine ) varnish layer , I couldn't even spread the oil varnish cause the oil was absorbed by the first coat which have a strong affinity for oil... Just a disaster , with bubbles at the surface, an uneven colour distribution and horrible patchy areas that lacks transparency in some areas. The worst varnishing experience I had...
  18. No worries, I personally don't feel offended When I saw the pictures I knew it (most probably) is an antique and valuable instrument. I was not convinced about Strad though, even if I didn't look at it in details, and to be honest when I saw the scroll , I thought it doesn't look like it is a Strad scroll, even if it's a great looking one (and this alone, made me say it is not a Strad...) so I was not surprised when I saw the description on Tarisio. Unfortunately there were many scroll replacements on antique instruments for some reasons ... If I remember well, Luigi Tarisio was reputed to have a big collection of ( cut ) scrolls... He apparently tried to repair some violins and got to know J. B. Vuillaume. Anyway, the pictures look like professional pictures from a web site. What is , perhaps, a hoax is the story of " being offered a Strad " or even any kind of valuable violin, especially when we know very talented musicians have so many difficulties finding a valuable instrument that they could afford. If that Story was true , I would propose myself as a candidate for being offered a 17th century violin, viola or cello. Just for the sake of studying them in details as a violin-maker.
  19. It says: " the head by Francesco Gobetti of Venice ". Which makes much more sense to me ...
  20. Looks like a very nice violin !!! Whatever it is ! Surely not a Strad... The violin, if we judge by the photos, doesn't look like a hoax at all.
  21. ... You shouldn't give that gouge stroke , but by the time you thought about it... ...it ' s done. It is a bit like posting a comment on MN.
  22. I feel the same about this pragmatic approach , Bartolomeo surely was someone busy and who dared ... To go a bit further in this pragmatic approach I would say I wouldn't be surprised if some ( known or unknown names) involved in the family business or in the surrounding area ( artisans ? ) spent time to sharpen and maintain in good conditions of use, the cutting tools, others would manage the raw jobs, such as measuring timber pieces, selecting and cutting wood pieces , or cooking the varnish and so on... I presume we are certainly over-thinking things , compared to people like Bartolomeo , trying to pay attention to only the critical aspects of their craft and life... David.
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